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5:50 AM PT -- We're told Justin has been released from the hospital. He feels crappy, but still plans on going ahead with tonight's show.

Justin Bieber was taken to a hospital in London moments ago ... after collapsing backstage during a concert ... TMZ has learned.

A source close to

Reality stars Rob Kardashian and Honey Boo Boo's Mama June have guts ... to be so public with their weight battles.

Rob -- who has been working out hard trying to lose the 40 lbs. he gained since his breakup with Rita Ora -- showed off his manly curves in a clingy white t-shirt at the

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Brooke Mueller is placing all media outlets on notice ... publish her naked photos and she'll SUE YOUR PANTS OFF!!!

Sources close to Charlie Sheen's ex-wife tell TMZ, she's FURIOUS someone is attempting to sell her intimate photos to the media -- and if anyone tries to publish them, she has

Miley Cyrus made a HUGE statement last night without ever saying a word ... 'cause she went out in public WITHOUT her engagement ring ... in the wake of rumors her fiance cheated on her.

Miley DID have some jewelry on her hand when she went out in L.A. last night ... in fact, she even